Cultivation, Management, Seedling and techniques of Sweet Potato

1. Varieties and seedlings: sweet potato varieties should be selected according to the type of export, used for processing vermicelli and vermicelli products, and high starch sweet potato varieties should be selected, such as Jishu 98, Xushu 18, Xinnong 1, Xinyin 1, Shang SL-19, etc. Xushu Beijing 553, Xinong 431, Sushu 8, Xinnong 4, American black potato can be selected for baking. There is a great relationship between the quality of potato seedlings and yield. If the seedlings are strong, the seedlings grow fast, root early, bear potatoes early and have strong stress resistance, while old vines, weak seedlings, slow stem and leaf growth, and poor stress resistance. 2. deep ploughing and fertilization generally apply 4000 kg of high-quality soil fertilizer, 40 kg of ammonium bicarbonate, 60 kg of superphosphate and 20 kg of potassium sulfate every 667m2. Deep ploughing more than 25 cm, ridging, ridge height 30 cm, upper width 40-50 cm, ridge bottom width 90 cm, ditch bottom width 30 cm, double rows planted on the ridge surface when planting seedlings. The yield of strong seedlings was 26.5% higher than that of weak seedlings in fields with medium fertility, and 9.6% higher than that of weak seedlings in fields with higher fertility. Therefore, the cultivation of strong seedlings is one of the key techniques to achieve high yield of sweet potato. Potato block seedling bed should choose places with leeward direction, high terrain, good drainage and convenient management, and adopt two seedling methods of film mulching and burying potato in the open field. The bed width is 1.2m-1.3m, and the length depends on the need. The average amount of seeds used in the field is about 150kg per hectare. Generally, every 10kg seed potato can supply about 5000 slim plants. In the seedling bed management, it is necessary to do a good job in heat preservation, moisturizing, ventilation and seedling cutting. 3. Timely and early planting sweet potato belongs to unlimited growth crop. At suitable temperature, the longer the growth period is, the higher the yield is. Spring potato covered with plastic film can be planted 10-15 days in advance, and then break the film to release seedlings when there is no frost, which can increase the yield by more than 30% compared with non-film mulching cultivation; in open field cultivation, spring potato should plant good seedlings, high cutting and strong seedlings, and the seedling height is about 25 cm. When planting, one row is planted on each side of the ridge, with 3500-4000 spring potatoes and 4000-5000 summer potatoes per 667m2. Plant shallowly as far as possible, leave 5 cm on the ground, the rest are buried in the soil along the ridge, buried 5-8 cm deep, pour enough water, cover tightly with fine soil after water infiltration, and leave 3-4 leaves on the ground. Finally, every 667 square meters, 80-100g trifluralin was sprayed on the surface of 60 kilograms of water to prevent weeds. After planting for about 5 days, you should check and replenish the seedlings. 4. Water enough when watering and fertilizing and planting. In case of drought in the next 20 days or so, water along the ditch. Pay attention to drainage in flood season. Sweet potato needs a large amount of fertilizer, so there are four words in fertilization: sufficient, suitable, heavy and skillful. Sufficient: the potato field should apply sufficient base fertilizer, accounting for 40% of the total fertilizer application, 50% of the total amount of fertilizer. Suitable: 10-15 days after planting, it is suitable to apply hole fertilizer, 5-7 kg of urea per 667m2, or 1000-1200 kg of rarefied livestock and poultry manure. Weight: heavy application of edge fertilizer, applied before the stem elongation to the stem and leaf closure, accounting for about 40% of the total, mainly organic fertilizer, combined with appropriate amount of chemical fertilizer. Qiao: in the later stage of sweet potato growth, crack fertilizer was skillfully applied when cracks appeared on the border surface, applying 1500 kg of rarefied livestock and poultry manure (water) or 10 kg of urea per hectare. 0.2% of "sweet potato bulge" or potassium dihydrogen phosphate can also be foliar sprayed to promote the expansion of potato lumps. 5. Before the sweet potato is planted in the stem and leaf, the sweet potato should be ploughed for 2-3 times to weed, mainly by shallow hoe to maintain the original ridge shape. In case of rain or moist soil, sweet potatoes grow into many adventitious roots. The vine should be lifted in time, and 15% paclobutrazol should be sprayed to prevent the stem from growing. The suitable concentration is 230g for 60kg water. Sweet potato sliced direct seeding cultivation sweet potato (sweet potato) sliced direct seeding cultivation, planting 20-30 days earlier than traditional planting, due to prolonging its growth period, generally increase the yield of fresh potato by about 1000 kg per mu. It is a comprehensive high-yield cultivation technique with low investment, high efficiency, labor and time saving. First, select potato species. Select good varieties suitable for local cultivation, the size of potato pieces should be uniform, each piece weighs about 100-150 grams, and remove potato blocks damaged by freezing injury, diseases and insect pests. Generally use 50kg per mu to soak the seeds in pieces. According to the different density of bud eyes at the upper and lower ends of potato blocks, the upper part of potato pieces should be cut smaller, and the lower part should be larger, leaving 2-3 bud limits in each piece. Soak the cut potato mother in 500-600 times carbendazim solution for 10-20 minutes. Sow seeds as soon as they are taken out to dry. Third, fertilize the soil and apply sufficient base fertilizer. 4000-6000 kg of organic fertilizer and 50 kg of ternary compound fertilizer are applied per mu. Deep ploughing and secret ridge cultivation are adopted. The ridge width is not less than 80 cm and the height is 28-30 cm. Fourth, sow seeds in time. The time of slicing and direct seeding is one month earlier than the time of planting seedlings, and the seed potato had better be sowed to the ground within two days after coming out of the cellar to avoid cold injury. Before sowing, open a ditch 15 cm wide and 5-6 cm deep on the back of the ridge. after pouring enough water into the ditch, put the mother bud eye face south up in the ditch, and the plant spacing is 25-30 cm. Immediately after planting, it is covered with film to protect moisture and raise temperature. Fifth, strengthen management. The height of the seedling is about 2 cm, and the membrane should be broken manually in time to avoid burning the seedlings. The film should be released in time when the ground temperature rises at the end of May and the beginning of June. At the same time, pay attention to weeding and insect control. Do not turn over the rice seedlings so as not to reduce the yield. The medium-term management method of sweet potato is the middle growth stage of sweet potato, which is the expansion stage of sweet potato, from the ridge sealing of stems and leaves to the peak of stem and leaf growth, and the corresponding thickening and expansion of sweet potato. Spring potatoes are generally 60-90 days after planting, and summer potatoes are 40-70 days after planting. The growth center of this stage is the stem and leaf, and the stem and leaf growth reaches the peak in the middle and late August. This stage is in the high temperature and rainy season, the fertilizer decomposes quickly, the water supply is sufficient, the phenomenon of overgrowth is easy to occur, the upper leaves are black, the petiole of leaf nodes is longer, the leaf layer is thick, the leaves are shaded and ventilated by each other, and there are many rotten leaves in the lower layer of yellow leaves, fallen leaves, dead stems and rotten leaves, and the potato expands slowly, which is easy to cause small seedlings and reduced yield. Therefore, the management of this period is the key to the high yield of sweet potato. 1. Drought prevention and drainage. During this period, it was hot and rainy in most parts of the north, the stems and leaves of sweet potato grew rapidly, and the nutrients were not upward and downward. At this time, attention should be paid to drainage, that is, timely removal of stagnant water on the ground after rain to control the vigorous growth of the aboveground. For dry years, watering is needed to prevent drought, so that potato cubes can expand rapidly in non-wet and dry soil. 2. Lift the vine and break the root, so you can't turn the vine. In the high temperature and rainy season, the soil moisture is too high, some varieties take root too much, or the high-yield fields are rich in fertilizer and water, and the white roots are many and deep. Lifting vines can reduce the water and nutrients of leaves, control the excessive growth of stems and leaves, dry the ridge soil and improve soil permeability. During this period, the vine can not be turned, because the vine damages the stems and leaves, disturbs the uniform distribution of the leaves, affects the photosynthetic efficiency of the leaves, and reduces the yield. 3. Paclobutrazol was sprayed many times. For overgrown plots, use 15% paclobutrazol 50-70 grams per mu to spray 50 kg of water, generally 2-3 times, the effect is better. 4. Chase and promote potato fertilizer. Pay attention to topdressing in the middle of growth, mainly potassium fertilizer such as potassium sulfate, plant ash and so on. Because potash fertilizer can prolong leaf age, improve photosynthetic efficiency, promote the transport of photosynthetic matter, increase the ratio of potassium to nitrogen, and promote the rapid expansion of potato pieces. Application of potassium sulfate, 10 kg per mu, plant ash, 100-150 kg per mu. 5. Control leaf-eating pests. In recent years, the occurrence of sweet potato diamondback moth in some plots is serious, which should be observed and controlled in time after discovery. Before the third instar, the larvae were sprayed with 2.5% trichlorfon powder, 1.5 kg per mu, or 1500 times of 90% crystal trichlorfon, or 1000 times of 50% phoxim, at 4 pm. In the later stage of sweet potato, the field management caught 3: 1. Apply good expansion fertilizer: 15 kg of calcium superphosphate and 10 kg of ammonium sulfate per mu, and 0.3% potassium dihydrogen phosphate and 1% urea solution can be sprayed. two。 Clear ditch and reduce waterlogging damage: during the root expansion period of sweet potato, there is more rainfall, so the field drainage ditch should be dredged in time to reduce waterlogging damage. 3. Control of leaf roll moth: when the population density of sweet potato leaf roll moth is high, it can eat all the leaves of the whole field, and when the larvae have not rolled leaves before the 3rd instar, spray 32% EC 3200 times to control. Spraying should be carried out after 5pm on a sunny day. The fields with high population density and serious harm can be sprayed again every 3-5 days. Fertilization technology in the late growth stage of sweet potato in the late growth stage of sweet potato, reasonable fertilization can prevent plant premature senescence, maintain the assimilation ability of leaves, promote the transport of nutrients to the root tuber, and thus increase the yield. After foliar spraying sweet potato entered the later growth stage, the absorption capacity of root system weakened, so foliar fertilizer spraying could be carried out. 0.5% urea can be sprayed on weak hilly slopes, plain sandy lands or fields with a tendency of premature senescence, and 0.2% potassium dihydrogen phosphate solution or 2%-3% calcium superphosphate leaching solution can be sprayed on fields with strong growth and high fertility levels. in general, fields can be sprayed with a mixture of 0.4% urea and 0.5% potassium dihydrogen phosphate, once every 7 to 10 days, for a total of 2 times. Each time the fertilizer solution is sprayed 70 kilograms per mu, and the suitable spraying time is sunny evening. The fertilizer-water irrigation seam was applied along the ridge with 3%-5% potassium sulfate solution or 10%-20% plant ash leaching solution, with 100kg fertilizer solution per mu. For fields with a tendency of premature senescence, 2% ternary compound fertilizer solution can be used. The main points of high-yield management of summer sweet potato: first, to prevent the excessive growth of stems and leaves, the growing season of summer sweet potato is in the season of high temperature and more Rain Water, and the stems and leaves grow rapidly, if not controlled in time, it is easy to cause prosperous growth. In general, when sweet potato seedlings grow to 50 to 60 centimeters, 10 milliliters are sprayed for every 667 square meters, or 20,25 milliliters for zhuangsu. For fertilizer-deficient seedlings, 10 kg of urea or 20 kg of diammonium phosphate per 667m2, and 1000 kg of feces and urine of acquaintances, the method is to open a hole next to the back of the ridge. After fertilizing and watering, the water seeps down and covers the soil immediately. Second, protection of stems and leaves from turning sweet potato seedlings due to damage to stems and leaves, reduction of photosynthesis, production of less nutrients, resulting in reduced yield. at the same time, turning seedlings will also cause leaf overturning, overlap and density, hurt the top tip of the seedling, and promote the emergence of new branches and leaflets in axillary buds, resulting in a yield reduction of up to 20% and 30%. Third, timely prevention and control of diseases and insect pests in recent years, the occurrence of sweet potato diamondback moth is relatively serious. Once found, 4.5% cypermethrin EC 3000 times or 20% fenvalerate 2000 times should be sprayed in time to ensure that sweet potatoes have sufficient leaf area. At the same time, aphids should be controlled in time during the growth period to prevent the introduction of the virus. From late August to early October, sweet potato is the root expansion period of sweet potato tuber in spring and summer, which is the key period of yield formation, and it needs the most fertilizer. First, hole topdressing method: with a piece of manure, 20-30 cm from the main root, drill a hole about 30 cm deep, put in an appropriate amount of three-element compound fertilizer, and seal it with wet soil. if you drill a hole on both sides of the ridge, the effect will be better. This method increases the yield by about 20% per mu. Second, crack fertilizer method: when cracks appear in the expanded ground of sweet potatoes, use 500 grams of potassium dihydrogen phosphate per mu, add 400 kilograms of water, or 2.5 kilograms of urea and 10 kilograms of calcium superphosphate, add 500 kilograms of water, and form fertilizer liquid to irrigate cracks, 0.7-1 kilograms per plant. Half a month later, 100 kg of grass ash per mu was added to 500 kg of water (soaked for 4 hours). The filtrate was sewn and sealed, and the yield was increased by more than 300 kg per mu. Third, foliar topdressing method: foliar spraying 0.3% potassium dihydrogen phosphate (or 2.5% potassium sulfate, 10% herbal ash, 2% sulfuric acid press, 0.3% superphosphate, 0.3% a urea) aqueous solution, sprayed once a week, this method increases the yield by 18% per mu. In order to increase the yield of sweet potato, we should pay attention to 5 points after late August, which is the key period for the expansion of summer sweet potato. At this time, the management should be strengthened. On the one hand, we should maximize the nutrients needed for the expansion of sweet potato, on the other hand, we should prevent premature senescence of stems and leaves, enhance photosynthesis and increase nutrient accumulation. The specific technical suggestions for increasing yield are as follows: 1. The removal of the top core can regulate the operation of nutrients and promote the transport of nutrients to the root tuber. Peeling the top was carried out twice, the first time when the potato vine grew to 30 cm long and 40 cm long, the first time when the branch grew to about 30 cm long, and the second time when the branch grew to about 30 cm, the tender tip was removed. 2. Pruning for potato fields with more branches and more prosperous growth, 2-3 branches can be cut off with scissors, so that nutrients can be returned, potato pieces can get more nutrients, light transmission between potato branches and potatoes can be improved, photosynthesis can be accelerated and so on. But the poor soil is not suitable to pick the heart. 3. After the potato seedlings are sealed with potassium fertilizer in August, potassium dihydrogen sulfate solution can be sprayed, that is, potassium dihydrogen sulfate solution is prepared into 1: 2% solution of potassium dihydrogen sulfate to water, spraying 50-70 kg per mu, once every 5-7 days, for 3 consecutive times. For fields with insufficient base fertilizer, thin stems and leaves, or late de-fertilization, a mixture of 0.3% potassium dihydrogen phosphate solution and 0.5% urea fertilizer solution is used. Spray 50-70 kg per mu, once every 5-7 days, for 2 times in a row. 4. The method of lifting vine can be used to prevent the root from running too much in the over-growing potato field. If the sweet potato grows too much after sealing the ridge, you can gently lift the potato vine and put it back in the same place. The time to lift the vine should be controlled before the end of August, for a total of 2 or 3 times. 5. The time of topdressing crack fertilizer is generally 80 days after planting, when the potato pieces enter the peak period of expansion, and when cracks appear on the border surface. The details should be determined according to the growth and soil quality of summer sweet potatoes. For example, the fields with insufficient fertilizer, thin soil layer and poor plant growth can be applied early, and the amount of topdressing can be 800~l000 kg of rotten human and animal manure per mu, or 7kg of urea to 600kg of water. If the fields with sufficient fertilizer and exuberant plant growth in the early stage, they can apply less or only soil miscellaneous fertilizer and potash fertilizer, but not nitrogen fertilizer.